Fix mapping for VAR_KEYWORD type kwargs. (#66)

* Fix mapping for VAR_KEYWORD type kwargs.

This allows plotting with variable names, not jsut cf names

* Pin pandas < 1.1.0

Author: dcherian

cf_xarray/accessor.py

@@ -742,10 +742,11 @@ def _rewrite_values(
                 maybe_update = {
                     # TODO: this is assuming key_mappers[k] is always
                     # _get_axis_coord_single
-                    k: apply_mapper(mapper, self._obj, v)[0]
+                    k: apply_mapper(
+                        key_mappers[k], self._obj, v, error=False, default=[v]
+                    )[0]
                     for k, v in kwargs[vkw].items()
                     if k in key_mappers
-                    for mapper in key_mappers[k]
                 }
                 kwargs[vkw].update(maybe_update)
 

cf_xarray/tests/test_accessor.py

@@ -283,6 +283,12 @@ def test_dataarray_plot(obj):
     assert all([isinstance(line, mpl.lines.Line2D) for line in rv])
     plt.close()
 
+    obj = obj.copy(deep=True)
+    obj.time.attrs.clear()
+    rv = obj.cf.plot(x="X", y="Y", col="time")
+    assert isinstance(rv, xr.plot.FacetGrid)
+    plt.close()
+
 
 @pytest.mark.parametrize("obj", datasets)
 def test_dataset_plot(obj):

ci/doc.yml

@@ -12,6 +12,7 @@ dependencies:
   - numpydoc
   - ipython
   - ipykernel
+  - pandas<1.1.0
   - pip:
       - git+https://github.com/xarray-contrib/cf-xarray
       - sphinx-book-theme

ci/environment.yml

@@ -7,4 +7,5 @@ dependencies:
   - dask
   - matplotlib
   - netcdf4
+  - pandas<1.1.0
   - xarray